Coin, Sri Lanka, Rupee
1982 - AU(55-58) - Copper-nickel - KM:136.2
Inscription below designs within wreath
- Composition: Copper-nickel
- Year: 1982
- Country: Sri Lanka
- Denomination: Rupee
- Mint name: Not Applicable
- Product type: Coin
- Catalog Initials: KM
- Coinage Type: Decimal Coinage
- EdgeDesc: Reeded
- Period: 1982
- First Issue Date: 1977
- Mintage: 75000000
- KM: 136.2
Cupronickel (or copper-nickel), also known by the French registered term cuivre blanc (white copper), is an alloy far less modern then one might initially think. Appearances can be misleading! There are examples dating from the Warring States period in China between the 5th and 3rd century BC. Back then, it was used for weapons. In its natural state, the alloy was probably of extraterrestrial origin, arriving on Earth with falling meteorites.
As the Chinese traded with the neighboring Bactrian kingdom, it is there that the first traces of cupronickel coins are found.
Jumping ahead a few millennia and some meteor dust, it first appeared in the West in the US in 1857.
With the price of copper at its highest ever, cupronickel was chosen for the new one cent coin. The alloy at the time contained 88% copper to 12% nickel, and the coin was smaller in diameter than its predecessor (there are no small savings, right?).
Cupronickel is now extremely popular and frequently used for coinage.
Dark gray in color, this alloy, generally comprising around 75% copper to 25% nickel, is highly resistant to corrosion.
An “AU(55-58)” quality
As in numismatics, it is important that the state of conservation of an item be carefully evaluated before it is offered to a discerning collector with a keen eye.
This initially obscure acronym comprising two words describing the state of conservation is explained clearly here:
This means – more prosaically – that the coin has been in circulation but sufficiently little that its original beauty is preserved almost in its entirety. The wear is barely visible and any other defect can only be identified with a magnifying glass or a particularly keen eye. The number (55-58) indicates that between three quarters and almost all of the original luster remains.